The county board of supervisors, on the adoption and purchase of an optical scan voting system, may issue bonds under section 331.441, subsection 2 , paragraph “b” , subparagraph (1). [S13, §1137-a14; C24, 27, 31, 35, 39, § 906; C46, 50, 54, 58, 62, 66, 71, 73, 75, 77, 79, 81 , S81, §52.3 ; 81 Acts, ch 117, §1009 ] 83 Acts, ch 123, §46, 209 ; 2007 Acts, ch 190, §27 ; 2009 Acts, ch 57, §48 Referred to in §331.383